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6.2L alternator upgrade

AJMBLAZER

AJMBLAZER

Better to be lucky than good.
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Nothing's going wrong right now, just sorta thinking ahead since I've replaced two alternators on different vehicles in the past month along with a battery and know of two other vehicles that need batteries. Makes me a bit nervous so I'm looking into it just in case.

The Blazer has the dual batteries but one 70something amp alternator. Seems a bit small. Looking at NAPA's website there's several 100 amp options and then a 140 amp option. Is that right? Double the price though.:doah:

Anyway, all I plan on doing is adding some lights on each end and that's about it. I just prefer overkill when I have to repair.
 
Do you have a serp. belt setup? Just because I looked under the hood a year ago doesn't mean I can remember :doah:
 
You have less options with the existing brackets, but if you were to upgrade to the newer serpentine belt setup you can go 130+ amps fairly easy.
 
Uhmmmm...that just got a lot lower on the priority list.

Probably mess with the AC compressor too huh?
 
You might get away with keeping the same AC compressor and p/s pump and just need to change the brackets.
 
Lots to think about.

Keep fantasizing about one of those new super dooper 6.5L's one day.
Don't know how much I want to sink into this engine. Just treat it right and run it until it dies.
 
There is nothing wrong with the 70 amp alternator you have in there either. Unless you have a big stereo...
 
Not really. Nice Dual head unit, some good 6.5's and the stock dash speakers holding on for dear life.

Just basically considering that if this thing ever manages to die I'd like to put something bigger in. If you're doing it...why not?
 
If you want the largest that will bolt in without a lot of headache, I think 100 or 120 amp is the limit.
 
Yeah, probably just do that. At most it'll have two 55w lights on each end.

Come to think of it I ought to check what the alt actually is. The guy who owned it and had all the radio crap in it musta needed a lot of juice with all the wires running all over it.
 
The 6.2 requires very little eletrical power to run since there is no EFI or ignition like on a gas version. The only thing to keep it running is enough power to keep the fuel shutoff solenoid open.

In any case, the above posts talking about all the work required for a larger alternator are not true. Several years ago I installed a "large case" CS144 (140 amp) alternator in my '90 without much difficulty. Can't remember the name but ordered a new AC Delco alternator with the correct v-belt pulley and the wiring pigtail to match up the connectors. From what I remember here are the details for install:
1. enlarge the adjuster slot (that loosens or tigthens the belt) on the stock bracket since the CS144 uses a slightly larger bolt
2. shim up the bracket a little where it bolts to the top of the engine (is it one of the manifold studs??)
3. replaced the heater line fitting that comes out towards the passenger side thermostat/pump area....stock fitting I think is straight and just replaced it with a 45 degree fitting
4. clearanced the bracket a litttle for room for above

The only difference is you have to keep the alternator belt pretty tight to avoid it squealing while trying to turn the big alternator.
 
I was going to say--I think the 140 amp altenator I got from a Olds FWD with a v-6 looks identical externally to the 10-SI on my 6.2,though I might find I'm mistaken if I go to bolt it up..but comparing them side by side it appears I could use it,as long as the v-belt pulley off my original is compatable with the shaft on the Olds one,which has a serpentine belt,and I have swapped many serpentine pulleys for v-belt ones in the past..the biggest headache would be figuring out which of the wires on the smaller plug are the field and activation ones ,the 140 amp one has a newer style plug with three or four wires--but I think I read here in other threads GM makes an adapter plug or you can wire up one yourself..

I see no real need to upgrade to anything bigger than my truck has now though--if I were running an electric/hydraulic plow pump or had a lot of lights,etc,I'd consider it..but so far my single 60 something amp one seems to charge both batteries just fine..I would almost rather build a custom bracket to mount a second altenator rather than have to swap everything over to serpentine belt--maybe a military version with the dual 24V altenator systems bracketry could be used to add another altenator more easily??..
 
Only thing I noticed with Big Ugly's dual alternator setup is they aren't regular GM alternators from our trucks. Some special use stuff so I doubt much would line up. You'd have to figure out what else would fit or just use the military alts and figure out how to make the system work as 12v with two alts. However again, they aren't common alts.
 
I've only seen the dual military setup in photos,so I was not certain what they used for altenators..probably some bizzare thing !...I suppose custom bracketry could be made up easy enough from boneyard parts, or scratch too..but I'd say 90% of us will never need more than a 70 amp altenator anyway..why go through all this to solve a "problem" that doesn't really exist--because it "might"??...as I get older (and lazier) I dont go changing things unless they really DO need to be changed or upgraded.
 
Yeah, I think if I do anything it'd just be whatever was more amps and bolt in.
One day future 6.5L shooper dooper engine I'll deal with a serp setup.

I BELIEVE I heard somewhere that the military alts are in fact a GM parts bin part...but some sort of 70's ambulance application or something. Not something NAPA's likely to have on the shelf.
 
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